linux.git/drivers/usb/serial/generic.c, branch v3.19 Linux kernel source tree usb: serial: handle -ENODEV quietly in generic_submit_read_urb 2015-01-12T09:23:54+00:00 Jeremiah Mahler jmmahler@gmail.com 2015-01-11T13:42:07+00:00 04f9c6e6d17584340fb6c8a9469a0e6df28876d2 If a USB serial device (e.g. /dev/ttyUSB0) with an active program is unplugged, an -ENODEV (19) error will be produced after it gives up trying to resubmit a read. usb_serial_generic_submit_read_urb - usb_submit_urb failed: -19 Add -ENODEV as one of the permanent errors along with -EPERM that usb_serial_generic_submit_read_urb() handles quietly without an error. Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com> Signed-off-by: Johan Hovold <johan@kernel.org> 
If a USB serial device (e.g. /dev/ttyUSB0) with an active program is
unplugged, an -ENODEV (19) error will be produced after it gives up
trying to resubmit a read.

  usb_serial_generic_submit_read_urb - usb_submit_urb failed: -19

Add -ENODEV as one of the permanent errors along with -EPERM that
usb_serial_generic_submit_read_urb() handles quietly without an error.

Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
usb: serial: silence all non-critical read errors 2015-01-12T09:23:35+00:00 Jeremiah Mahler jmmahler@gmail.com 2015-01-11T13:42:06+00:00 aa8e22128b40590b291cd13512098bf258a7e6c5 If a USB serial device is unplugged while there is an active program using the device it may spam the logs with -EPROTO (71) messages as it attempts to retry. Most serial usb drivers (metro-usb, pl2303, mos7840, ...) only output these messages for debugging. The generic driver treats these as errors. Change the default output for the generic serial driver from error to debug to silence these non-critical errors. Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com> Signed-off-by: Johan Hovold <johan@kernel.org> 
If a USB serial device is unplugged while there is an active program
using the device it may spam the logs with -EPROTO (71) messages as it
attempts to retry.

Most serial usb drivers (metro-usb, pl2303, mos7840, ...) only output
these messages for debugging.  The generic driver treats these as
errors.

Change the default output for the generic serial driver from error to
debug to silence these non-critical errors.

Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
USB: serial: add missing braces 2014-03-12T19:44:50+00:00 Johan Hovold jhovold@gmail.com 2014-03-12T18:09:41+00:00 ca0400d2caf0d6f18445feea79c8c5a4ccf77e61 Add missing braces to conditional branches and one loop in usb-serial core and generic implementation. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <greg@kroah.com> 
Add missing braces to conditional branches and one loop in usb-serial
core and generic implementation.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
USB: serial: continue to write on errors 2014-03-12T19:44:49+00:00 Johan Hovold jhovold@gmail.com 2014-03-12T18:09:40+00:00 bd58c7bd6fd5f803b4127717bda9cc6c30d0c806 Do not discard buffered data and make sure to try to resubmit the write urbs on errors. Currently a recoverable error would lead to more data than necessary being dropped. Also upgrade error messages from debug to error log level. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <greg@kroah.com> 
Do not discard buffered data and make sure to try to resubmit the write
urbs on errors.

Currently a recoverable error would lead to more data than necessary
being dropped.

Also upgrade error messages from debug to error log level.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
USB: serial: continue to read on errors 2014-03-12T19:44:49+00:00 Johan Hovold jhovold@gmail.com 2014-03-12T18:09:39+00:00 fc11efe2800f2f9ba2ccb268321642b7e9f73a65 Make sure to try to resubmit the read urb on errors. Currently a recoverable error would lead to reduced throughput as only one urb will be used until the port is closed and reopened (or resumed or unthrottled). Also upgrade error messages from debug to error log level. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <greg@kroah.com> 
Make sure to try to resubmit the read urb on errors.

Currently a recoverable error would lead to reduced throughput as only
one urb will be used until the port is closed and reopened (or
resumed or unthrottled).

Also upgrade error messages from debug to error log level.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
USB: serial: fix write memory-allocation flag 2013-11-25T16:39:40+00:00 Johan Hovold jhovold@gmail.com 2013-11-09T11:38:10+00:00 043e3f834530e15e89c58c1b7af59cc646700134 Fix regression introduced by commit 818f60365a29 ("USB: serial: add memory flags to usb_serial_generic_write_start"), which incorrectly used GFP_KERNEL in write(), which must not not sleep. Reported-by: Dave Jones <davej@fedoraproject.org> Tested-by: Dave Jones <davej@fedoraproject.org> Cc: Dave Jones <davej@fedoraproject.org> Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Fix regression introduced by commit 818f60365a29 ("USB: serial: add
memory flags to usb_serial_generic_write_start"), which incorrectly used
GFP_KERNEL in write(), which must not not sleep.

Reported-by: Dave Jones <davej@fedoraproject.org>
Tested-by: Dave Jones <davej@fedoraproject.org>
Cc: Dave Jones <davej@fedoraproject.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: serial: fix race in generic write 2013-11-25T16:39:40+00:00 Johan Hovold jhovold@gmail.com 2013-11-09T11:38:09+00:00 6f6485463aada1ec6a0f3db6a03eb8e393d6bb55 Fix race in generic write implementation, which could lead to temporarily degraded throughput. The current generic write implementation introduced by commit 27c7acf22047 ("USB: serial: reimplement generic fifo-based writes") has always had this bug, although it's fairly hard to trigger and the consequences are not likely to be noticed. Specifically, a write() on one CPU while the completion handler is running on another could result in only one of the two write urbs being utilised to empty the remainder of the write fifo (unless there is a second write() that doesn't race during that time). Cc: stable <stable@vger.kernel.org> # 2.6.35 Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Fix race in generic write implementation, which could lead to
temporarily degraded throughput.

The current generic write implementation introduced by commit
27c7acf22047 ("USB: serial: reimplement generic fifo-based writes") has
always had this bug, although it's fairly hard to trigger and the
consequences are not likely to be noticed.

Specifically, a write() on one CPU while the completion handler is
running on another could result in only one of the two write urbs being
utilised to empty the remainder of the write fifo (unless there is a
second write() that doesn't race during that time).

Cc: stable <stable@vger.kernel.org> # 2.6.35
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: serial: export usb_serial_generic_write_start 2013-10-12T00:00:26+00:00 Johan Hovold jhovold@gmail.com 2013-10-09T15:01:12+00:00 706cd17e8559c96dc883ba692c931f1ef31fbc5c Export usb_serial_generic_write_start which is needed when implementing a custom resume function while still relying on the generic write implementation. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Export usb_serial_generic_write_start which is needed when implementing
a custom resume function while still relying on the generic write
implementation.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: serial: add memory flags to usb_serial_generic_write_start 2013-10-12T00:00:26+00:00 Johan Hovold jhovold@gmail.com 2013-10-09T15:01:11+00:00 818f60365a29ab1266d92c6a91094fbf93465ff8 Add memory-flags parameter to usb_serial_generic_write_start which is called from write, resume and completion handler, all with different allocation requirements. Note that by using the memory flag to determine when called from the completion handler, everything will work as before even if the completion handler is run with interrupts enabled (as suggested). Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Add memory-flags parameter to usb_serial_generic_write_start which is
called from write, resume and completion handler, all with different
allocation requirements.

Note that by using the memory flag to determine when called from the
completion handler, everything will work as before even if the
completion handler is run with interrupts enabled (as suggested).

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: serial: clean up comments in generic driver 2013-10-12T00:00:26+00:00 Johan Hovold jhovold@gmail.com 2013-10-09T15:01:10+00:00 92ad247995c587e07cb67dcc8aafac4db636e394 Clean up some comments, drop excessive comments and fix-up style. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Clean up some comments, drop excessive comments and fix-up style.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>